U.S. patent application number 14/357349 was filed with the patent office on 2014-10-16 for melatonin-based solutions and powders for their preparation.
The applicant listed for this patent is Eratech S.R.L.. Invention is credited to Giovanni Caponetti, Loretta Maggi.
Application Number | 20140308357 14/357349 |
Document ID | / |
Family ID | 45373751 |
Filed Date | 2014-10-16 |
United States Patent
Application |
20140308357 |
Kind Code |
A1 |
Maggi; Loretta ; et
al. |
October 16, 2014 |
MELATONIN-BASED SOLUTIONS AND POWDERS FOR THEIR PREPARATION
Abstract
The present invention relates to a powder for reconstitution
before use for preparations for injection containing melatonin, at
least one soluble excipient and at least one surfactant for the
treatment of neonatal cerebral infarction. The present invention
also relates to a preparation for injection in the form of a
solution obtained by dissolving a powder to be reconstituted
comprising melatonin, at least one soluble excipient and at least
one surfactant, in a mixture of water and polyalkylene glycol, in
which the melatonin is present in quantities of from 3 to 30 mg/ml
and the polyalkylene glycol is present in quantities from 5 to 40%
of the total volume of the liquid used.
Inventors: |
Maggi; Loretta; (Piacenza,
IT) ; Caponetti; Giovanni; (Piacenza, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eratech S.R.L. |
Milano |
|
IT |
|
|
Family ID: |
45373751 |
Appl. No.: |
14/357349 |
Filed: |
November 9, 2012 |
PCT Filed: |
November 9, 2012 |
PCT NO: |
PCT/EP2012/072327 |
371 Date: |
May 9, 2014 |
Current U.S.
Class: |
424/489 ;
514/415 |
Current CPC
Class: |
A61K 9/1641 20130101;
A61K 47/20 20130101; A61K 9/0019 20130101; A61K 47/10 20130101;
A61P 35/00 20180101; A61P 9/00 20180101; A61K 47/183 20130101; A61P
25/28 20180101; A61K 9/08 20130101; A61K 9/14 20130101; A61K 47/26
20130101; A61K 47/34 20130101; A61K 47/38 20130101; A61P 25/20
20180101; A23C 9/206 20130101; A61K 31/4045 20130101; A61K 9/0031
20130101; A61K 9/1617 20130101; A61K 9/1623 20130101 |
Class at
Publication: |
424/489 ;
514/415 |
International
Class: |
A61K 47/26 20060101
A61K047/26; A61K 9/14 20060101 A61K009/14; A23C 9/20 20060101
A23C009/20; A61K 47/10 20060101 A61K047/10; A61K 47/34 20060101
A61K047/34; A61K 31/4045 20060101 A61K031/4045; A61K 47/18 20060101
A61K047/18 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2011 |
IT |
MI2011A002042 |
Claims
1. A powder for use as a medicament, wherein it comprises melatonin
in an amounts from 35 to 90% in weight, at least one water soluble
excipient in an amount from 5 to 60% in weight and at least one
water soluble surfactant in an amount from 0.5 to 5% of the total
weight of the powder, said powder having an X90 of less than 100
.mu.m and a VDM of less than 50 .mu.m.
2. The powder according to claim 1, wherein it comprises particles
in which melatonin, a water soluble excipient and a water soluble
surfactant are present.
3. The powder according to claim 1, wherein it is obtained by spray
drying from a solution comprising melatonin.
4. The powder according to claim 1, wherein said water soluble
excipient is chosen from the group consisting of: alitame,
acesulfame potassium, aspartame, saccharin, sodium saccharin,
sodium cyclamate, sucralose, trehalose, xylitol, citric acid,
tartaric acid, cyclodextrin, dextrin, hydroxy ethyl cellulose,
gelatine, malic acid, maltitol, maltodextrin, maltose,
polydextrose, tartaric acid, sodium or potassium bicarbonate,
sodium or potassium chloride, sodium or potassium citrate,
phospholipids, lactose, sucrose, glucose, fructose, mannitol,
sorbitol, natural amino acids, alanine, glycine, serine, cysteine,
phenylalanine, thyroxin, tryptophan, histidine, methionine,
threonine, valine, isoleucine, leucine, arginine, lysine, aspartic
acid, glutamic acid, asparagine, glutamine, proline, their salts
and any simple chemical modifications, as in the case of N-acetyl
cysteine and carbocysteine, and mixture thereof.
5. The powder according to claim 1, wherein said water soluble
surfactant is chosen from the group consisting of nonionic
surfactants.
6. A powder for use as a medicament, wherein it comprises melatonin
in an amount from 75 to 84% in weight, mannitol in an amount from 8
to 20% in weight leucine in an amount from 4 to 12% in weigh and
poloxamer 188 in an amount from 0.5 to 1.5% of the total weight of
the powder, said powder having an X90 from 10 to 35 .mu.m and a VDM
from 5 to 20 .mu.m.
7. A pharmaceutical composition in the form of a solution wherein
it is obtained by dissolving a powder comprising melatonin in an
amount from 35 to 90% in weight, at least one water soluble
excipient in an amount from 5 to 60% in weight and at least one
water soluble surfactant in an amount from 0.5 to 5% of the total
weight of the powder, said powder having an X90 of less than 100
.mu.m and a VDM of less than 50 .mu.m, in a mixture of water and
polyalkylene glycol, in which melatonin is present in an amount
from 3 to 30 mg/ml and the polyalkylene glycol is present in an
amount from 5 to 40% of the total volume of the liquid used.
8. A process for preparation of a powder according to claim 7,
wherein comprising the following steps: a. preparing a first phase
(a) in which the melatonin is present in a suitable liquid medium;
b. preparing a second phase (b) in which soluble excipients are
dissolved and surfactants are dissolved or dispersed in an aqueous
medium; c. mixing said phases (a) and (b) to obtain a third phase
(c) in which the liquid medium is homogeneous; d. drying said phase
(c) in controlled conditions to obtain a dry powder with particles
whose dimensional distribution has a VDM of less than 50 .mu.m and
an X90 of less than 100 .mu.m; e. collecting said dry powder and
packaging it in a form suited to the extemporaneous preparation of
a solution.
9. A kit for the extemporaneous preparation of a solution, said kit
comprising a powder containing melatonin in an amount from 35 to
90% in weight, at least one water soluble excipient in an amount
from 5 to 60% in weight and at least one water soluble surfactant
in an amount from 0.5 to 5% of the total weight of the powder, said
powder having at least one X90 less than 100 .mu.m and a VDM of
less than 50 .mu.m, and a liquid medium comprising H.sub.2O and
polyalkylene glycol in quantities from 5 to 40% of the total volume
of the liquid used.
10. A pharmaceutical composition in the form of a solution wherein
comprising melatonin in an amount from 2 mg/ml to 20 mg/ml, said
solution having an osmolality of less than 1400 mOsm/kg.
11. The composition according to claim 10, wherein said solution
having an osmolality of less than 900 mOsm/kg.
12. The composition according to claim 10, wherein said solution
having an osmolality from 300 to700 mOsm/kg.
13. The composition according to claim 10, wherein a polyalkylene
glycol is present in an amounts from 5 to 40% of the total volume
of the liquid used.
14. The composition according to claim 10, wherein t is obtained by
dissolving a powder comprising melatonin in an amounts from 35 to
90% in weight, at least one water soluble excipient in an amount
from 5 to 60% in weight and at least one water soluble surfactant
in an amount from 0.5 to 5% of the total weight of the powder, said
powder having an X90 of less than 100 .mu.m and a VDM of less than
50 .mu.m.
15. The composition according to claim 6 wherein said glycol is
polyethylene glycol (PEG) with a molecular weight from 200 to
600.
16. The composition according to claim 7, wherein a thickening or
gelling agent is present in an amount from 0.5 to 50% w/v of the
preparation.
17. The composition according to claim 16, wherein said thickening
or gelling agent is chosen from the group consisting of:
carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC),
hydroxyethylcellulose, hydroxypropylcellulose, microcrystalline
cellulose (Avicel), chitosan, Sodium Alginate, Alginic acid,
carrageenan, Guar gum, Gelatin, Hyrpomellose, Polyvinylpirrolidone
(PVP), Poloxamers, Polyethylene glycols (MW>600).
18. The composition according to claim 7, for use in the treatment
of neonatal cerebral infarction.
19. The composition according to claim 7, for use in the treatment
or prevention of perinatal asphyxia.
20. The composition according to claim 7, for use in the treatment
or sleep disorders in a pediatric patient.
21. The composition according to claim 7, for use in the treatment
of sleep disorders in Autism Spectrum Disorders (ASD)
22. The composition according to claim 7, for use in
preanesthesia.
23. A composition for oral administration comprising the
composition according to claim 7 and breast feed milk.
Description
[0001] The present invention relates to a powder for reconstitution
before use for preparations of a solution comprising melatonin.
More in particular, the present invention relates to a powder for
reconstitution before use for preparations of a solution,
comprising melatonin for use in the treatment of cerebral
infarction. Melatonin-based solutions are also part of the
invention.
[0002] Melatonin is a hormone secreted by the pinealocytes of the
pineal gland, or pinealocytes, during the night, with a 24-hour
circadian rhythm trend, characterised by very low levels during the
day and an increase at night that starts at around 8.00 p.m. and
reaches peak values between 2 and 4 in the morning.
[0003] In plasma, the concentration of melatonin, which circulates
bound to albumin, varies in the range 10-300 pg/ml.
[0004] Its half-life is short (30-60 minutes), due to the 90%
clearance following its first passage through the liver.
Approximately 75% of the melatonin metabolised by the liver cells
is converted into 6-hydroxymelatonin, then conjugated with sulphate
(70%) and, to a lesser extent, with glucuronic acid (6%).
Bioavailability is low and equal to approximately 15%. Melatonin
appears to be rapidly absorbed if administered as oral solutions,
and the peak blood concentration is the highest of those reported
for similar doses in healthy individuals. After oral
administration, its peak blood concentration (Cmax) is influenced
by the solubility of the melatonin in the formulation,
bioavailability alterations and clearance.
[0005] In the past melatonin has been studied for pharmaceutical
purposes, by developing preparations for oral administration. These
preparations include formulations with cyclodextrin and as
microemulsions. Nevertheless, and common to many other
preparations, it may be necessary to wait longer than 30 minutes
from administration to achieve peak blood concentration of
melatonin. This is due in part to the need for gastrointestinal
absorption to be complete, for the melatonin to be available in the
bloodstream. Moreover, the bioavailability of melatonin is low and
very variable. The absolute availability of melatonin via the oral
route was shown to be approximately 15% due to a significant effect
of a first hepatic passage, and peak plasma concentrations can vary
by as much as almost 20-fold. For this reason, the oral
administration of melatonin through the currently available
formulas does not provide a rapid onset of action and the variable
absorption makes this route of administration impractical.
[0006] The increase in blood melatonin levels, achieved by taking
both physiological and pharmacological doses, favours the induction
of sleep, as well as its duration and quality, providing a
well-documented hypnotic action, similar to that of
benzodiazepines.
[0007] Thanks to its hypnotic action, melatonin has been proposed
as the main agent or as a coadjuvant for many applications
including conditions that are typically related to the paediatric
age such as: [0008] dyssomnias and difficulties initiating and
maintaining sleep. Among these, delayed sleep-phase syndrome (DSPS)
and advance sleep-phase syndrome (ASPS). [0009] Neurological
impairments that affect irregular sleep-wake patterns such as:
mental or intellectual disabilities, mental retardation, learning
disabilities, autistic spectrum disorders, Rett syndrome, tuberous
sclerosis, developmental disabilities and Angelman syndrome.
[0010] In addition, melatonin has been evaluated for its usefulness
in the treatment of sleep trouble of Autism Spectrum Disorders
(ASDs).
[0011] Sleep problems including delayed sleep onset, sleep or
bedtime resistance, prolonged tiredness upon waking and daytime
sleepiness as well as Attention Deficit Hyperactivity Disorder
(ADHD), Smith Magenis Syndrome (SMS) and Sanfilippo Syndrome (SFS)
can also be treated using melatonin.
[0012] Other potentially relevant uses of melatonin are related to
the premedication preceding the anesthesia induction.
[0013] The evidence reported that patients with seizures of diverse
origin show an alteration of the melatonin rhythm is supportive of
its use also for this application.
[0014] Since newborns and particularly those delivered preterm have
less protection against oxidation and are highly susceptible to
free radical-mediated oxidative damage, melatonin, because of its
antioxidant properties could be useful to reduce oxidative stress
in neonates with sepsis, asphyxia, respiratory distress or surgical
stress.
[0015] This anti-radical action is synergic to that of vitamin E,
which protects the entire cell from oxidative stress with various
mechanisms, including the boosting of enzyme systems such as
glutathione peroxidase and superoxide dismutase. In vitro
experiments have definitively confirmed the inhibiting effect of
melatonin on lipid peroxidation with a synergic effect to that of
retinoids.
[0016] It is well documented that melatonin exhibits a circadian
rhythms in body fluids, and human milk is no exception. Melatonin
in the milk of lactating mothers exhibits marked daily rhythm with
high levels during the night and undetectable levels during the
day. This melatonin rhythm in milk could serve to communicate time
of day information to breast-fed infants, this information could
also contribute to the consolidation of sleep-wake rhythm of
infants until the maturation of their own circadian rhythm.
[0017] Melatonin plays an important role as a scavenger of both
reactive oxygen species and reactive nitrogen species, including
peroxynitrite (ONOO--). Moreover, it increases the activity of
various antioxidant enzymes such as superoxide dismutase (SOD) or
glutathione peroxidase (GSH-Px) and it induces the activity of
gamma-glutamylcysteine synthetase thereby stimulating the
production of another antioxidant, glutathione (GSH). Melatonin not
only regulates the activity of these enzymes, but also their mRNA
levels.
[0018] In addition to the above mentioned characteristics,
melatonin is considered an important antioxidant as it is a
lipophilic and hydrophilic molecule and able to easily cross all
biological barriers, including the blood-brain barrier. Moreover,
it is available in all bodily tissues and cells, distributing
itself to all the cell parts, but primarily in the nucleus and
mitochondria.
[0019] Thanks to the antioxidant characteristics mentioned above,
melatonin can be used advantageously in the treatment of cerebral
infarction and cerebral paralysis. The term "cerebral infarction"
is intended as an infarction of any tissue or part of the brain.
Cerebral infarction is caused by cerebral ischaemia or hypoxaemia.
As is well known, the main causes of cerebral ischaemia are
cerebral thrombosis and cerebral embolism.
[0020] For the treatment of these events, melatonin has been
positively studied in form of a micro-encapsulated system, such as
the liposomal form.
[0021] The advantages of this administration are related to the
possibility of releasing the melatonin into the bloodstream
gradually so that its apparent residence time therein increases and
leads to an increase in the same bioavailability of the active
ingredient.
[0022] Other examples of encapsulated systems proposed for
melatonin are related to the creation of cyclodextrin matrices or
to the use of synthetic or natural biodegradable polymers such as
polylactic acid or copolymers of lactic acid and glycolic acid.
[0023] EP1174134B1 describes a pharmaceutical or dietary
composition for the treatment of cerebral infarction. Said
pharmaceutical composition is administered via the oral route, in
order to reduce the effects of the infarction. However, this type
of administration presents a number of limits, since modest blood
concentrations of melatonin are obtained due to its rapid hepatic
metabolism. Consequently, low levels of the medicinal product are
able to cross the blood-brain barrier and reach the damaged brain
areas. Moreover, due to its poor solubility, a significant portion
of the dose administered via the oral route is swallowed
undissolved in saliva and is responsible for the low and variable
bioavailability of melatonin via the gastrointestinal route.
[0024] Melatonin is, in fact characterised by poor solubility in a
solvent medium that is constituted primarily by water.
[0025] This poor solubility has significantly restricted its use
since, despite having a high anti-oxidant pharmacological activity,
the doses needed to obtain this kind of activity must be quite
high.
[0026] Thanks to its antioxidant activity, melatonin could be
successfully used in the prophylaxis of certain neurological
diseases and to prevent acute cerebral events, however the
necessity to administer quite high doses restricts its use, as does
the impossibility of being able to develop liquid formulations in
which to dissolve a large amount in a small volume.
[0027] As a consequence, melatonin is currently commercially used
only in nutraceutical or "over-the-counter" products for the
symptomatic treatment of jetlag. This syndrome is, in fact, treated
with oral administration of 3 mg tablets without requiring any
particular industrial processing.
[0028] However, in the case of the use of melatonin as an
antioxidant agent, although significant scientific evidence exists
to support this pharmacological effect, at the current time there
are no products available on the market containing melatonin with
an antioxidant function.
[0029] To demonstrate the difficulties of developing formulations
containing melatonin for antioxidant use, a number of patents
mention the possibility of using melatonin at high doses but do not
describe the procedure used for the preparation of such doses.
[0030] More in particular, in the case of the administration of
melatonin to a premature newborn, there is a conflict between the
difficulty to reconcile requirements such as the administration of
a high dose of melatonin and the impossibility of injecting into
this particular patient a volume of liquid too large.
[0031] With respect to the administration of a pharmaceutical agent
in a paediatric setting, and more specifically to a preterm child,
3 type of formulations are to be considered acceptable: [0032] oral
solutions [0033] injectable solutions [0034] rectal solutions.
[0035] When considering oral administration, oral liquid dosage
forms would normally be considered acceptable for children from
full term birth.
[0036] According to the Reflection paper: formulations of choice
for the paediatric population (EMEA/CHMP/PEG/194810/2005), typical
target dose volumes for paediatric liquid form
TABLE-US-00001 Age Volume (ml) Preterm newborn infants 2 Term
newborn infants (0 d-28 d) 4 Infants and toddlers (1 m-2 y) 5
Children (pre school) (2-5 y) 5 Children (school) (6-11 y) 4
Adolescents (12-16/18 y) 4
[0037] Based on the table presented, it appears very clear that the
only applicable approach for paediatric administration of oral
solutions is significantly limited by the acceptable volume of
delivery. Especially when dealing with low solubility active
principles.
[0038] Nevertheless an oral liquid dosage form will normally need
to be preserved. It is very well documented that preservatives have
a potential to cause toxicological problems, especially in young
children.
[0039] As an alternative to the oral route, the rectal route of
administration can be utilized to achieve a systemic effect in
children. Also immediate systemic effects can be achieved as
documented by the administration of diazepam to resolve epileptic
seizures.
[0040] Also in this case volume limitations have to be taken into
consideration.
[0041] Typical target dose volumes for paediatric liquid enemas are
presented in the table here below:
TABLE-US-00002 Age Volume (ml) Preterm newborn infants 5 Term
newborn infants (0 d-28 d) 4 Infants and toddlers (1 m-2 y) 4
Children (pre school) (2-5 y) 3 Children (school) (6-11 y) 3
Adolescents (12-16/18 y) 2
[0042] The volume of the enemas is related to its function and to
the age of the child. Nevertheless, volumes of enemas for systemic
therapy in paediatric patients should be as small as possible to
achieve accurate delivery, good absorption and absence of
irritation.
[0043] The solutions can be administered as they are or eventually
their viscosity can be increased with the addition of a thickening
agent like a cellulose polymer to form a gel.
[0044] Excipients used in rectal dosage forms should not irritate
the rectal mucosa of infants and children.
[0045] Also parenteral formulations are suitable for paediatric
administration.
[0046] The most appropriate method on injection for emergency
practices are to be considered the intravenous injection and the
infusion.
[0047] For seriously ill paediatric patients the intravenous route
is preferred and if possible, injections are administered through
an indwelling venous cannula.
[0048] Both for i.v. solutions and for pump systems, volume
limitations are to be considered according to the table here
below:
TABLE-US-00003 Age Volume (ml) Preterm newborn infants 5 Term
newborn infants (0 d-28 d) 4 Infants and toddlers (1 m-2 y) 4
Children (pre school) (2-5 y) 4 Children (school) (6-11 y) 4
Adolescents (12-16/18 y) 3
[0049] The venous access may be by a small cannulae in a peripheral
vein.
[0050] Peripheral veins with slow blood flow will be irritated by a
high osmotic load, extremes of pH and the chemical nature of some
active substances and excipients. Phlebitis, thrombo-phlebitis or
infiltration of the tissue may result with loss of the vein for
therapy and possibly tissue damage.
[0051] With respect to osmoticity, this characteristic of the
formulation has special importance in the i.v. infusion of highly
concentrated nutritional solutions.
[0052] The hyperosmoticity problem is generally solved by injecting
the solution centrally into a large volume of rapidly moving blood,
instead of using peripheral infusions.
[0053] Use of such solutions and knowledge of their value have led
to the use of similar formulations administered, not parenterally
but orally. Nevertheless, when certain solutes are ingested in
large amounts or as concentrated fluids, their osmotic
characteristics can cause and upset in the normal water balance
within the body.
[0054] In these cases, when highly osmotic solutions are ingested,
large amounts of water will transfer to the stomach and intestines
from the fluid surrounding those organs, in an attempt to lower the
osmoticity.
[0055] The higher the osmoticity, the larger the amount of water
required. A large amount of water in the GI tract can cause
distention, cramps, nausea, vomiting, hypermotility and shock.
[0056] Hyperosmoticity feeding may result in mucosal damage in the
GI tract following both oral and rectal administration.
[0057] With respect to the preparation of a solution for
injectable, oral or rectal administration another critical aspect
of these preparation relates to stability of melatonin in
solution.
[0058] Good evidences are reported that indicate that melatonin
solutions gradually lose potency at all pH values and are not
stable when exposed to light or oxygen.
[0059] It would therefore be necessary to develop, for this
therapy, a melatonin formulation at a concentration of at least 5
mg/ml, which is not toxic and can be administered intravenously to
a premature newborn.
[0060] The development of aqueous solutions with a high melatonin
concentration was tackled following different approaches.
[0061] The first approach adopted was that of dissolution in a
water-alcohol solution in which ethanol made up as much as 35% of
the total volume. It is therefore obvious that this approach is not
compatible with a treatment intended for a premature infant.
[0062] The simplest solution adopted, on the other hand, was to
completely avoid using ethanol and to use in replacement of the
same, as a co-solvent, a glycol to be mixed with water.
[0063] This approach would make it possible, in theoretical terms,
to obtain even quite concentrated solutions of melatonin without
using toxic organic solvents.
[0064] U.S. Pat. No. 5,939,084 describes compositions containing
melatonin for both pharmaceutical and cosmetic use, in solutions of
water and PEG at different concentrations.
[0065] However, the proposed approach is not without
contraindications, since melatonin thus formulated was not stable
either in quantitative terms, with loss of content, or in
qualitative terms, with the development of degradation
products.
[0066] In addition, due to the presence of isoprene glycol,
butylene glycol or propylene glycol in the composition the
osmolality of the solutions presented don't have an acceptable
level of osmolality for an injectable application or an oral and
rectal administration
[0067] As regards the melatonin stability in aqueous solution, it
is acknowledged by literature (Daya S., Walker R B, Glass B D,
Anoopkumar-Dukie S., The effect of variations in pH and temperature
on stability of melatonin in aqueous solution; J. Pineal Res. 2001;
31:155-158) that aqueous solutions of this active substance present
stability problems. The melatonin content in aqueous solutions at a
concentration of 50 .mu.g/ml and a pH of 7.4 show, after just 5
days, a loss in melatonin content of 9% and 10% when stored at
20.degree. C. and 37.degree. C., respectively.
[0068] Moreover, with the same solution, at the pH values 4.0 and
7.4 a loss of melatonin potency of 22% or 29% respectively was
observed upon storage at 20.degree. C.
[0069] A degradation of this extent in such a short time is clearly
incompatible with the development of a product in solution form
whose stability should be guaranteed for at least 6 months.
[0070] Moreover there is a risk, which has been reported in certain
cases, that melatonin in solution may partially recrystallise with
precipitation adding to the risk of a loss of active substance
content also that of administrating to the patient an intravenous
solution containing suspended particles.
[0071] Consequently, from this point of view, storing melatonin
solutions at a low temperature (e.g. 4.degree. C.) to maintain
their chemical stability could compromise the preparation's
physical stability.
[0072] We have surprisingly found that it is possible to retain
melatonin stability at concentrations higher than 2 mg/ml together
with solution osmolality acceptable for injection application or
oral and rectal administration.
[0073] In order to guarantee both the chemical and physical
stability of the melatonin in the solution, the most suitable
technological approach would be to make up melatonin solutions
extemporaneously, to be administered at the time of use.
[0074] However, this option is precluded in the case in which pure
melatonin in a crystalline form is to be used, since it has a low
dissolution speed both in aqueous solutions and in water and PEG
solutions.
[0075] Melatonin's low dissolution speed represents the second
important problem concerning the preparation of high concentration
aqueous solutions for administration by injection.
[0076] In the case of injection therapy in newborns, the issues of
administering high doses of melatonin are heightened by the
patient's inability to cooperate in the administration of the
medicinal product and, above all, the minimum plasma volumes, which
restrict the volume of liquid that can be injected.
[0077] To this we can also add the need for a rapid formulation
dissolution with a reduction in the size of the formulate that must
be present in the form of a clear solution.
[0078] Given this need, any dry melatonin micronisation technique
is clearly precluded as the product that can be obtained by this
route would be in crystalline form and therefore very slow to
dissolve.
[0079] It would therefore be preferable to have a stable melatonin
formulation, in order to obtain a therapeutically acceptable
dose.
[0080] It would, moreover, be preferable to have a pharmaceutical
formulation for injection able to satisfy the injectability
criteria for medicinal products and that it is therefore devoid of
substances that are harmful or toxic for the organism.
[0081] It would also be preferable to dispose of a pharmaceutical
melatonin liquid formulation in form of solution, for the treatment
of neonatal conditions, therefore with limited injected or
administered volumes in order to avoid generating imbalances in the
blood volumes of the patients treated.
[0082] Thus a general aim of the invention is to provide melatonin
solution for injectable, rectal or oral preparations with
acceptable values of pH and osmoticity of this preparation.
[0083] According to this invention such general aim is obtained by
a pharmaceutical composition in the form of a solution
characterised by comprising melatonin in an amount from 2 mg/ml to
20 mg/ml, said solution having an osmolality of less than 1400
mOsm/kg, preferably of less than 900 mOsm/kg more preferably from
300 mOsm/kg to 700 mOsm/kg.
[0084] According to this invention the osmolality is defined as the
concentration of a solution in terms of osmoles of solute per
kilogram of solvent. It is expressed in terms of Osm/kg or
mOsm/kg.
[0085] Another aim of the present invention is to provide a stable
and easy to administer melatonin formulation, with adequate
concentrations of active substance, such as to be able to reach
therapeutically acceptable doses.
[0086] A further aim of the present invention is to provide a
melatonin formulation for injection that respects the requirements
envisaged for such form of administration and that is therefore
devoid of toxic substances or those not compatible with parenteral
or intravenous administration.
[0087] Yet another aim of the present invention is to provide a
melatonin formulation for injection for the treatment of neonatal
conditions that is compatible with such subjects and presents
reduced administration volumes.
[0088] According to this invention, the above mentioned aims are
achieved by means of a powder for use as a medicament, containing
melatonin in an amounts from 35 to 90% in weight, at least one
water soluble excipient in an amount from 5 to 60% in weight and at
least one water soluble surfactant in an amount from 0.5 to 5% of
the total weight of the powder, said powder having an X90 of less
than 100 .mu.m and a VDM of less than 50 .mu.m
[0089] According to this invention X90 is the limit values of 90%
of the dimensional distribution of the powder, and VMD is the
volume mean diameter of the powder.
[0090] A further aim of the present invention concerns a
composition in the form of a solution obtained by dissolving a
powder containing melatonin in an amounts from 35 to 90% in weight,
at least one water soluble excipient in an amount from 5 to 60% in
weight and at least one water soluble surfactant in an amount from
0.5 to 5% of the total weight of the powder, said powder having an
X90 of less than 100 .mu.m and a VDM of less than 50 .mu.m, in a
mixture of water and polyalkylene glycol, in which melatonin is
present in an amounts from 2 to 30 mg/ml and the polyalkylene
glycol is present in an amounts from 5 to 40% of the total volume
of the liquid used. According to this invention X90 and VMD are the
same as described above.
[0091] Another aspect of the present invention relates to a kit for
the extemporaneous preparation of a solution for injection,
including: a powder containing melatonin in an amounts from 35 to
90% in weight, at least one water soluble excipient in an amount
from 5 to 60% in weight and at least one water soluble surfactant
in an amount from 0.5 to 5% of the total weight of the powder, said
powder having an X90 of less than 100 .mu.m and a VDM of less than
50 .mu.m, and a liquid medium comprising H.sub.2O and polyalkylene
glycol in quantities from 5 to 40% of the total volume of the
liquid used.
[0092] Preferably, in order to obtain a pharmaceutical form of
melatonin that can be used in the treatment of cerebral infarction
and in particular in neonatal cerebral infarction, the
concentration of melatonin in the pharmaceutical form is from 2
mg/ml to 20 mg/ml, preferably from 5 mg/ml to 15 mg/ml more
preferably from 8 mg/ml to 12 mg/ml.
[0093] The solution according to the present application it is also
suitable for using in the treatment of prevention of perinatal
asphyxia, neonatal cerebral infarction, treatment or sleep
disorders in a pediatric patient, treatment of sleep disorders in
Autism Spectrum Disorders (ASD) and for use in preanesthesia.
[0094] The preferred production process for the powder for
reconstitution according to the present invention is that of spray
drying using a water-alcohol solution of a soluble excipient and a
surfactant in which the melatonin is dissolved or dispersed as a
suspension or emulsion.
[0095] With the spray drying technique it is possible to obtain
particles containing both melatonin and the soluble excipient. The
preferred morphology is an internally hollow one, in order to
obtain particles with a reduced density when poured onto the bed of
powder; in this way the melatonin is dispersed in said soluble
excipient or combined and interpenetrated with it.
[0096] From the point of view of stability, the melatonin is indeed
entrapped or combined and interpenetrated into a matrix that
includes all the excipients that at the same time guarantee the
stability of the powder preparation during its handling and
storage, thereby avoiding the need to keep the product in
controlled conditions of temperature and/or humidity.
[0097] The soluble excipient or excipients present in the powder
for reconstitution according to the present invention usually have
a solubility in water greater than 5 mg/ml and often greater than
100 mg/ml or over. They are preferably chosen from sugars, salts,
amino acids and certain soluble polymers and can perform multiple
functions, such as: [0098] facilitating the rapid dissolution of
the dry composition; [0099] favouring the formation of particles
with a small diameter during preparation for spray drying; [0100]
improving the chemical and physical stability of the melatonin in
the powder formulation; [0101] making sure that the melatonin can
be kept in a preferred crystalline or amorphous solid state; [0102]
improving the hydrophobicity of the surface of the particles
containing melatonin, protecting it from any harmful effects of
environmental humidity; [0103] favouring the fluidity of the powder
containing melatonin.
[0104] As regards the composition in its dry solid form, the
excipient constitutes the structural element for the formation of a
solid matrix, inside which the melatonin is interpenetrated.
Examples of soluble excipients that can be used in the composition
according to the present invention are: alitame, acesulfame
potassium, aspartame, saccharin, sodium saccharin, sodium
cyclamate, sucralose, trehalose, xylitol, citric acid, tartaric
acid, cyclodextrin, dextrin, hydroxy ethyl cellulose, gelatine,
malic acid, maltitol, maltodextrin, maltose, polydextrose, tartaric
acid, sodium or potassium bicarbonate, sodium or potassium
chloride, sodium or potassium citrate, phospholipids, lactose,
sucrose, glucose, fructose, mannitol, sorbitol, natural amino
acids, alanine, glycine, serine, cysteine, phenylalanine, thyroxin,
tryptophan, histidine, methionine, threonine, valine, isoleucine,
leucine, arginine, lysine, aspartic acid, glutamic acid,
asparagine, glutamine, proline, their salts and any simple chemical
modifications as in the case of N-acetyl cysteine and
carbocysteine.
[0105] The preferred soluble excipients are the salts of alkali
metals such as sodium chloride or potassium chloride and sugars
such as lactose.
[0106] Examples of preferred soluble polymers are hyaluronic acid
of any molecular weight, its salts and derivatives.
[0107] As far as the hollow morphology of the particles is
concerned, the composition requires the presence of a soluble
excipient, preferably a sugar such as lactose, able to form
instantaneously in the solvent evaporation stage during spray
drying, the skeleton of the particle and thereby producing
particles with a high porosity.
[0108] The surfactant present in the powder for reconstitution
according to the present invention can be chosen from various
classes of surfactants for pharmaceutical use.
[0109] Surfactants to be considered suitable for use in the present
invention are all those substances characterised by a medium or low
molecular weight that contain a hydrophobic portion, which is
generally readily soluble in an organic solvent but poorly soluble
or completely insoluble in water, and a hydrophilic (or polar)
portion, which is slightly soluble or completely insoluble in an
organic solvent but readily soluble in water. Surfactants are
classified according to their polar portion; therefore, surfactants
with a negatively charged polar portion are defined anionic
surfactants whereas cationic surfactants contain a
positively-charged polar portion. Uncharged surfactants are general
defined non-ionic, whereas the surfactants that contain both a
positively charged group and a negatively charged group are defined
zwitterionic. Examples of anionic surfactants are fatty acid salts
(better known as soaps), sulphates, sulphate ethers and phosphate
esters. Cationic surfactants are frequently based on polar groups
containing amine groups. The most common non-ionic surfactants are
based on polar groups containing oligo-(ethylene-oxide) groups.
Zwitterionic surfactants are generally characterised by a polar
group constituted by a quaternary amine and a sulphuric or
carboxylic group.
[0110] The following surfactants are examples of this application:
benzalkonium chloride, cetrimide, docusate sodium, glyceryl
monooleate, sorbitan esters, sodium lauryl sulphate, polysorbates,
phospholipids and bile salts.
[0111] Non-ionic surfactants such as polysorbates and
polyoxyethylene and polyoxypropylene block copolymers known as
"Poloxamers" are preferred. Polysorbates are described in the CTFA
International Cosmetic Ingredient Dictionary as mixtures of
sorbitol fatty acid esters and sorbitol anhydrides condensed with
ethylene oxide. Non-ionic surfactants belonging to the "Tween"
series are particularly preferred, especially the surfactant known
as "Tween 80", a commercial monooloeate polyoxyethylene sorbitan,
other preferred surfactants are: polyoxyethylene alkyl ethers (also
known with the trade name Brij), ricin oil polyoxyethylene ethers
(known with the trade name Cremophor), polyoxyethylene stearates
(known as PEG stearates) glyceryl monooleate and glyceryl
monostearate (known with the trade name Tegin or Myverol).
[0112] The presence of a surfactant, and preferably, Poloxamer 188
is necessary to guarantee the abatement of electrostatic charges,
maintenance of the powder's fluidity and maintenance of the solid
state in a homogeneous way, without initial crystallisation.
[0113] The powder for reconstitution according to the present
invention can comprise other components, such as pH buffers and
preservatives, however such components are generally not essential
due to the fact that the composition is stored in a dry solid form
and the relative aqueous solution is prepared extemporaneously
before use.
[0114] The process for preparation of the powder for reconstitution
according to the invention substantially comprises the operations
of: [0115] a) preparing a first phase (a) in which the melatonin is
present in a suitable liquid medium; [0116] b) preparing a second
phase (b) in which soluble excipients are dissolved and surfactants
are dissolved or dispersed in an aqueous medium; [0117] c) mixing
said phases (a) and (b) to obtain a third phase (c) in which the
liquid medium is homogeneous; [0118] d) drying said phase (c) in
controlled conditions to obtain a dry powder with particles whose
dimensional distribution has a median diameter of less than 50
.mu.m and an X90 of less than 100 .mu.m; [0119] e) collecting said
dry powder and packaging it in a form suited to the extemporaneous
preparation of a solution.
[0120] Operation d) consists in eliminating the liquid medium,
solvent or dispersant, from phase (c), to obtain a dry powder
having the desired dimensional characteristics. Such drying shall
be preferably obtained by spray drying. The characteristics of the
nozzle and the parameters of the operation are chosen so that the
liquid medium is evaporated from solution or suspension (c) and a
powder with the desired particle characteristics forms.
[0121] The term powder for reconstitution according to the present
invention is intended as a powder used for the extemporaneous
preparation of a stable solution of melatonin for injection in a
suitable volume of water or sterile saline solution.
[0122] As is known in the field, the extemporaneous preparation is
made up at the time of use, i.e. immediately before administration
of the medicinal product to the patient. In this description, the
term "extemporaneous preparation" also includes the preparation
made up by a pharmacist and destined to be administered to a
patient within a relatively short period of time from preparation.
More in general, the term "extemporaneous preparation" is used to
designate all those cases in which the solution is not manufactured
directly by the pharmaceutical company and marketed as such to be
used, rather to be prepared at a time subsequent to that in which
the dry solid composition is manufactured, usually a time close to
the time of administration to the patient.
[0123] In particular, the powder for reconstitution is dissolved in
a mixture of water and polyalkylene glycol in which the
polyalkylene glycol is present in a quantity from 5 to 40% of the
total volume, preferably in a quantity from 10% to 30%, such as to
obtain a preparation for injection in the form of a solution
containing melatonin.
[0124] In order to obtain a therapeutically acceptable
administration, the melatonin in the preparation for injection
obtained by dissolution of the powder for reconstitution according
to the present invention, is present in quantities from 2 to 30
mg/ml, preferably in a concentration from 5 to 15 mg/ml.
[0125] The polyalkylene glycol present in the dissolution medium
for the powder according to this invention advantageously
contributes to the dissolution of the melatonin in water, such as
to obtain higher concentrations of the active substance in the
solution for injection, in particular, the preferred polyalkylene
glycol is polyethylene glycol (PEG) with a molecular weight from
200 to 600.
[0126] In order to achieve a rectal preparation, a thickening or
gelling agent is added in the solution in amount from 0.5% to 50.0%
w/v of the composition: Examples of soluble thickening or gelling
agent that can be used in the composition according to the present
invention are: carboxymethylcellulose (CMC),
hydroxypropylmethylcellulose (HPMC), hydroxyethylcellulose,
hydroxypropylcellulose, microcrystalline cellulose (Avicel),
chitosan, Sodium Alginate, Alginic acid, carrageenan, Guar gum,
Gelatin, Hyrpomellose, Polyvinylpirrolidone (PVP), Poloxamers,
Polyethylene glycols (MW>600).
[0127] With regard to the oral administration, it is possible to
mix the solution according to the present invention with breast
feed milk, in order to achieve an oral administration for neonatal
or for children
[0128] The invention shall now be illustrated with reference to the
following non-limiting examples.
EXAMPLES
[0129] Preparation of the Powder for Reconstitution
[0130] Powders containing melatonin were obtained according to the
compositions indicated in Table 1, which also indicates the
quantities of dried product and volumes of solution produced.
[0131] Examples 1 and 2 concern the preparation of reference
powders constituted by pure melatonin produced by spray drying and
from melatonin with addition of the surfactant alone, without using
excipients.
[0132] All the preparations in the examples were implemented and
characterised in standard environmental conditions of 25.degree. C.
and 50% RH (relative humidity).
[0133] For the powder preparations, in all cases the melatonin was
first dissolved in ethanol and the excipients dissolved in water.
The two solutions thus obtained were combined slowly at an ambient
temperature of 25.degree. C., taking care not to cause the
precipitation of any of the components. The water-alcohol solution
thus obtained was processed using a Buchi model B290 spray drier
with condenser and recirculating closed circuit system.
[0134] The instrument was fitted with a nozzle with a diameter of
0.5 mm.
[0135] Atomization gas: nitrogen
[0136] Inlet temperature: 150.degree. C.
[0137] Nebulisation pressure: 2.5 bar
[0138] Powder collection system: cyclone separator coupled with a
nylon filter sleeve.
TABLE-US-00004 TABLE 1 Example Composition % Quantity (g) Solvent 1
- (comp.) Melatonin 100.0 50.0 500 ml EtOH 500 ml Water 2 - (comp.)
Melatonin 99.0 49.5 500 ml EtOH Tween 80 1.0 0.5 500 ml Water 3
Melatonin 50.0 25.0 500 ml EtOH Lactose 49.0 24.5 500 ml Water
Tween 80 1.0 0.5 4 Melatonin 70.0 35.0 500 ml EtOH Mannitol 24.0
12.0 500 ml Water Leucine 5.0 2.5 Tween 80 1.0 0.5 5 Melatonin 70.0
35.0 500 ml EtOH Lactose 8.0 4.0 500 ml Water Glycine 10.0 5.0
Leucine 10.0 5.0 Tween 80 2.0 1.0 6 Melatonin 70.0 35.0 500 ml EtOH
Lactose 24.0 12.0 500 ml Water Leucine 5.0 2.5 Tween 80 1.0 0.5 7
Melatonin 80.0 40.0 500 ml EtOH Lactose 16.0 8.0 500 ml Water
Leucine 3.0 1.5 Tween 80 1.0 0.5 8 Melatonin 80.0 40.0 500 ml EtOH
Mannitol 16.0 8.0 500 ml Water Leucine 3.0 1.5 Tween 80 1.0 0.5 9
Melatonin 50.0 25.0 500 ml EtOH Lactose 39.0 19.5 500 ml Water
Leucine 10.0 5.0 Tween 80 1.0 0.5 10 Melatonin 50.0 25.0 500 ml
EtOH Mannitol 39.0 19.5 500 ml Water Leucine 10.0 5.0 Tween 80 1.0
0.5 11 Melatonin 50.0 25.0 500 ml EtOH Mannitol 39.0 19.5 500 ml
Water Leucine 10.0 5.0 Poloxamer 188 1.0 0.5 12 Melatonin 60.0 30.0
500 ml EtOH Leucine 39.0 19.5 500 ml Water Poloxamer 188 1.0 0.5 13
Melatonin 80.0 40.0 500 ml EtOH Mannitol 10.0 5.0 500 ml Water
Leucine 9.0 4.5 Poloxamer 188 1.0 0.5
[0139] Characterisation of the Powder for Reconstitution
[0140] The powders obtained were characterised in terms of dry
particle size using a Sympatec Helos light-scattering appliance
that analyses the particles size according to the Fraunhofer
theory, fitted with a Rodos disperser.
[0141] The instrument was suitably calibrated with reference
material--Sic-F1200'08, Sympatec GmbH, System-Partikel-Tecnik- and
prepared according to the instructions provided in the instrument's
user manual.
[0142] Following appropriate cleaning before analysis, a quantity
of powder for each batch manufactured was analysed without
performing any preliminary preparation on the sample.
[0143] The dispersion gas used was compressed air suitably purified
of particles and oil residues.
[0144] The analysis mode defined therefore envisaged observing the
following parameters relative to the sample, powder disperser and
light scattering analyser. [0145] Sample [0146] size: approximately
100 mg [0147] analysis feeding procedure: with a spatula [0148]
sample pre-treatments: none [0149] Rodos disperser [0150] Model M
ID-NR 230 V/Hz 24Va [0151] Dispersion pressure: 3 bar [0152] Light
scattering analyser [0153] Model: Helos [0154] Analysis method:
Fraunhofer [0155] Software version: Windox 4.0 [0156] Analysis
lens: R3 (0.5-175 .mu.m) [0157] Minimum optical concentration: 1%
[0158] Analysis activation threshold: minimum optical concentration
detectable 1% for max 30 seconds of time and with at least 100 ms
of sample exposure.
[0159] All the analyses were conducted in an environment with a
controlled temperature and humidity corresponding to 25.degree. C.
and 50% RH relative humidity.
[0160] As far as the characterisation of the melatonin content and
corresponding degradation products are concerned, a suitable HPLC
analysis method was used.
[0161] The analytical method is characterised by the following
parameters: [0162] Analysis column: Zorbax Sb-Aq C18, 150 mm I.D.
4.6 .mu.m [0163] Column temperature: 25.degree. C. [0164] Mobile
phase: A: 0.018M phosphate buffer (2.45 g/l KH2PO4 in MilliQ water
at pH 3.0 for H3PO4) [0165] B: Acetonitrile [0166] Isocratic
elution: A:80% B: 20% [0167] Flow rate: 1.5 ml/min [0168]
Wavelength: 225 nm [0169] Injection volume: 5 .mu.L [0170]
Melatonin retention time: 2.3 min [0171] Analysis time: 5 mins
[0172] The instrument used for analysis was an Agilent model 1100
HPLC column with a diode array detector, model G1315B.
[0173] The samples of each powder to be analysed were obtained by
dissolving 10 mg of powder in 20 ml of the mobile phase prepared
for analysis.
[0174] The results for melatonin content and particle size are
presented in Table 2.
[0175] With reference to the particle size of the powders
manufactured it was considered acceptable to obtain melatonin
powder particles with limit values of 90% the dimensional
distribution (X90) of less than 100 .mu.m and volume mean diameter
(VMD) values of less than 50 .mu.m.
[0176] With reference to the melatonin content of the powders
produced, it is considered acceptable for the melatonin content
measured in the powders produced to be from 95% to 105% of the
expected value, according to the prepared composition.
TABLE-US-00005 TABLE 2 VMD X.sub.90 Melatonin Example (.mu.m)
(.mu.m) content (%) 1 (comp.) 35.5 81.2 100.9 2 (comp.) 63.3 152.3
99.0 3 28.3 59.2 102.0 4 10.8 23.3 100.0 5 13.0 24.2 99.3 6 9.7
18.9 101.1 7 10.2 20.0 99.2 8 8.2 15.5 99.0 9 5.5 10.1 101.6 10 5.7
10.3 102.7 11 3.7 7.1 100.5 12 3.0 5.5 101.4 13 10.5 17.9 101.8
[0177] Solubility of the Powder for Reconstitution
[0178] In order to evaluate the solubility of the powdered
melatonin formulations a series of melatonin powder samples was
prepared by dissolving different quantities in the same volume of 3
solutions containing respectively: [0179] Purified water [0180]
Water and PEG-400 (90/10) [0181] Water and PEG-400 (80/20) [0182]
Water and PEG-400 (75/25; 70/30; 60/40; 50/50)--example 11 and 13
only-- [0183] Water and Ethanol (90/10; 80/20; 75/25;
70/30)--example 11 and 13 only-- [0184] Water and PEG-200 (75/25)
[0185] Water and PEG-350 (75/25)
[0186] Following the preparation of a saturate solution of the
powders obtained, the same solution was filtered with a 0.22 mm
membrane and the filtered solution obtained was analysed by HPLC
according to the method described previously.
[0187] The results are indicated in Table 3.
[0188] In particular table 3a shows the solubility values of
melatonin roe material and the compositions of examples 1-13 in
pure water and in water/PEG-400 mixture with different water/PEG
ratios.
[0189] Table 3b shows the solubility values of melatonin row
material and the composition of the examples 11 and 13 in pure
water and in water/ethanol mixture with different water/ethanol
ratios.
[0190] Table 3c shows the solubility values of melatonin row
material and the composition of the examples 11 and 13 in water/PEG
mixture in ratio 75/25 with different type of PEG (PEG-200,
PEG-350, PEG-400.
[0191] The data reported do not show a change in the solubility of
the melatonin if used as a micronized crystalline raw material or
after formulation in a powder form obtained by spray drying.
[0192] The example shows that a relationship exists between the
maximum quantity of melatonin that can be dissolved and the amount
of PEG-400 used.
[0193] Dissolution can be complete if the relationship between the
amount of melatonin to be dissolved (expressed in mg) and the
volume of PEG-400 used (expressed in ml) does not exceed the ratio
50/1.
TABLE-US-00006 TABLE 3a Solubility mg/ml Composition Water-PEG-400
ratio Example Water 90-10 80-20 70-30 65-35 60-40 50-50 Melatonin
1.8 5.0 11.1 -- -- -- -- raw material 1 (comp.) 2.0 4.7 10.7 -- --
-- -- 2 (comp.) 2.0 5.1 11.3 -- -- -- -- 3 2.1 5.1 11.1 -- -- -- --
4 2.8 5.4 11.0 -- -- -- -- 5 1.8 4.7 10.5 -- -- -- -- 6 1.7 4.6
10.5 -- -- -- -- 7 1.7 4.8 10.1 -- -- -- -- 8 1.9 5.0 11.9 -- -- --
-- 9 2.0 5.2 11.8 -- -- -- -- 10 nd nd 10.1 -- -- -- -- 11 1.8 5.0
11.5 22.7 30.0 31.5 31.9 12 1.8 5.1 11.2 -- -- -- -- 13 1.7 5.1
10.0 18.4 25.8 29.4 22.5
TABLE-US-00007 TABLE 3b Solubility mg/ml Water-Ethanol ratio
Composition Example Water 90-10 80-20 75-25 70-30 Melatonin 1.7 3.7
8.2 14.2 19.7 raw material 11 1.8 2.5 5.4 13.7 13.9 13 1.7 2.5 5.0
7.7 11.9
TABLE-US-00008 TABLE 3c Solubility mg/ml Water-PEG 75/25
Composition Example PEG 200 PEG 350 PEG 400 Melatonin 10.5 16.9
14.5 raw material 11 10.5 13.3 15.1 13 10.7 11.4 14.2
[0194] Dissolution Speed of the Powder for Reconstitution
[0195] In order to document the difference in dissolution speed of
formulated melatonin compared to non-formulated melatonin, 30 mg of
pure melatonin and 60 mg of formulation 10 containing 30 mg of
melatonin, were dissolved in 3 ml of a solvent mixture of
water/PEG-400 (80/20).
[0196] The entire test was conducted in temperature conditions of
25.degree. C.
[0197] After 1 minute of manual stirring the two solutions were
left to settle for 1 minute.
[0198] The visual inspection of the two preparations after 1 minute
showed the presence of undissolved particulate in the case of the
non-formulated melatonin and it presented on the other hand a clear
solution in the case of the preparation containing the example 10
formulation.
[0199] After 1 minute of sedimentation, the supernatant solution
was sampled by taking 1 ml of it and analysing it according to the
HPLC method described previously.
[0200] The analysis revealed a concentration of melatonin present
in the supernatant solution derived from the dissolution of the
melatonin raw material of 7.1 mg/ml.
[0201] In the case, however, of the solution obtained from the
powder of example 10, the concentration of melatonin present in the
supernatant solution was equal to 10.2 mg/ml, corresponding to a
complete melatonin dissolution.
[0202] After 10 minutes of stirring, the solution of melatonin raw
material had a concentration of 7.9 mg/ml.
[0203] The test performed clearly showed that the pure melatonin
was not compatible with the making of an extemporaneous preparation
for administration by injection.
[0204] Stability of the Preparation for Injection
[0205] A test was conducted to evaluate the stability of a
melatonin solution obtained using the example 10 formulation as a
comparison with the stability of a melatonin solution obtained from
the pure raw material (melatonin raw material).
[0206] 60 mg of example 10 formulation melatonin were dissolved in
3 ml of water/PEG-400 (80/20) solvent mixture.
[0207] In the same way 30 mg of melatonin raw material were
dissolved in a volume of 3 ml of the same solvent composition.
[0208] For both the solutions obtained the dissolved melatonin
content was initially measured by means of the HPLC method
described previously.
[0209] This content was considered equivalent to 100% of the active
substance present in the solution.
[0210] The solutions were then stored at a temperature of 4.degree.
C. and 25.degree. C. and analysed after 9 and 24 days.
[0211] The results obtained are indicated in Table 4.
[0212] The results show that melatonin raw material has the
tendency to lose content in solution if stored at a low
temperature.
[0213] This content loss can be attributed to the possible
recrystallization of melatonin with precipitation.
[0214] In the case of the solution obtained from the dissolution of
the example 10 formulation, this loss of content is not seen.
TABLE-US-00009 TABLE 4 4.degree. C. 25.degree. C. Melatonin
Melatonin Time (days) raw material Example 10 raw material Example
10 0 100.0 100.0 100.0 100.0 9 98.9 100.0 100.0 100.0 24 98.3 100.0
99.5 99.5
[0215] Stability of the Powder for Reconstitution
[0216] To confirm the stability of the preparations of melatonin
powder a stability study was conducted on the bulk powders of the
example 9 and 10 formulations.
[0217] The powders were packaged in heat-sealed aluminium bags and
stored for 6 months in conditions corresponding to 4.degree. C. or
25.degree. C. and 60% relative humidity.
[0218] Periodically, a sample of both formulations was taken and
analysed to evaluate their: [0219] Dimensional distribution of the
particles according to the method described previously [0220]
Active substance content according to the HPLC method described
previously [0221] Residual water content using a Coulometric Karl
Fischer titrator, model C20X Mettler Toledo.
[0222] The results obtained are presented in Tables 5, 6, 7 and
8.
[0223] The analysis of the stability data collected for the two
formulations studied made it possible to demonstrate the excellent
stability of both formulations from a chemical and a physical point
of view.
[0224] As far as the active substance content is concerned, this
did not deteriorate significantly.
[0225] In the same way, the particle size characteristics of the
powders produced were not altered for the entire duration of the
study, in the same way as the moisture content of the two
formulations also remains essentially unchanged.
[0226] It is therefore possible to conclude that the stability of
melatonin in formulations of this type is guaranteed for up to 6
months.
TABLE-US-00010 TABLE 5 Formulation 9 Storage: 4.degree. C. T0 T = 1
month T = 3 months T = 6 months Content (%) 101.6 101.6 101.9 100.2
X90 (.mu.m) 10.1 10.9 10.1 10.7 VMD (.mu.m) 5.5 5.7 5.5 5.6 Water
1.0 1.0 1.0 1.0 content (%)
TABLE-US-00011 TABLE 6 Formulation 10 Storage: 4.degree. C. T0 T =
1 month T = 3 months T = 6 months Content (%) 102.7 103.7 103.5
101.8 X90 (.mu.m) 10.3 10.6 10.7 10.8 VMD (.mu.m) 5.7 5.7 5.7 5.9
Water 0.9 0.8 0.9 0.9 content (%)
TABLE-US-00012 TABLE 7 Formulation 9 Storage: 25.degree. C./60% RH
T0 T = 1 month T = 3 months T = 6 months Content (%) 101.6 102.0
100.4 99.9 X90 (.mu.m) 10.1 10.9 11.0 11.3 VMD (.mu.m) 5.5 5.8 5.7
5.9 Water 1.0 0.9 1.0 0.9 content (%)
TABLE-US-00013 TABLE 8 Formulation 10 Storage: 25.degree. C./60% RH
T0 T = 1 month T = 3 months T = 6 months Content (%) 102.7 103.1
102.2 101.2 X90 (.mu.m) 10.3 10.5 11.2 5.4 VMD (.mu.m) 5.7 5.9 6.0
11.3 6.0 Water 0.9 1.0 0.9 0.9 content (%)
[0227] As demonstrated by the tests, the powder for reconstitution
according to the present invention presents good morphological
characteristics, i.e. it is stable over time in terms of melatonin
content.
[0228] Furthermore, the powder is easily soluble in an aqueous
medium, thereby obtaining melatonin solutions with high
concentrations and that are substantially devoid of undissolved
particles.
[0229] The powder also presents a high dissolution speed, such as
to permit the preparation of extemporaneous solutions for injection
over a short timeframe.
[0230] In particular, the tests conducted on examples 9 and 10 show
how the powder for reconstitution according to the present
invention, compared to the reference powders of examples 1 and 2 or
to the melatonin raw material (non-formulated), is readily soluble
in a mixture of water and PEG thereby obtaining melatonin solutions
with concentrations suitable for administration in patients with
cerebral infarction, in particular suitable for administration in
newborns, thanks to the high concentrations achieved.
[0231] The solutions for injection obtained from dissolution of the
powder for reconstitution according to the present invention are
also stable after their preparation, thereby allowing use of the
same even several days after preparation.
[0232] Osmolality of Solutions for Administration
[0233] Following the concept of administering a solution with
controlled properties in terms of pH and osmolality raw melatonin
and the formulation of example 13 can be dissolved in compatible
Water/PEG 400 solvent mixtures leading to different administrable
solutions at different dosage for a fixed volume of delivery of 5
ml.
[0234] The results are presented in the tables that follow:
[0235] Melatonin Raw Material
TABLE-US-00014 Melatonin conc. Volume of Dose of Water/PEG in
solution injection melatonin 400 ratio (mg/ml) (ml) (mg) pH mOsm/Kg
90/10 5 5 25 5.2 335 85/15 7 5 35 5.2 530 80/20 10 5 50 5.2 754
75/25 14 5 70 5.2 1014 70/30 18 5 90 5.2 1310
[0236] Formulation of Example 13
TABLE-US-00015 Melatonin conc. Volume of Dose of Water/PEG in
solution injection melatonin 400 ratio (mg/ml) (ml) (mg) pH mOsm/Kg
90/10 5 5 25 5.2 344 85/15 7 5 35 5.2 542 80/20 10 5 50 5.2 773
75/25 14 5 70 5.2 1042 70/30 18 5 90 5.2 1350
[0237] Rectal Preparation
[0238] In order to document the possibility of preparing a
hydrophilic melatonin gel for rectal administration, 50 mg of pure
melatonin or 62.5 mg of formulation 13 containing 50 mg of
melatonin, were dissolved in 5 ml of a solvent mixture of
water/PEG-400 (75/25).
[0239] The entire preparation was conducted in temperature
conditions of 25.degree. C., without additional heating. Following
complete dissolution in the water/PEG 400 solvent mixture of
melatonin or formulation 13, 100 mg of Carboxymethilcellulose (CMC)
were gradually added in the two solutions and kept under continuous
agitation for 20 minutes. At the end of this time a clear gel was
formed.
* * * * *